Chromosomal Abnormalities and Multiple Gestations - 1

In our practice, we see many cases of multiple gestations (mostly twins and not more, thank goodness) that come about as the result of the success of our colleagues in Reproductive Endocrinology and Infertility (REI). In general, these patients tend to be older, have underlying medical problems, and are at greater risk for a wide range of complications during pregnancy including diabetes, pregnancy-induced hypertension, cervical incompetence, and premature labor and delivery. Their pregnancies are also at greater risk for babies with congenital birth defects and chromosomal abnormalities beyond the typical risks associated with “advanced maternal age.”

Recently, we were asked to perform a “targeted ultrasound” to assess fetal growth and anatomy on a set of IVF twins in a 40 year old woman (who had had many years of primary infertility) at about 20 weeks gestation. After conception, and documentation of fetal viability by our REI group, she reestablished care in the office of her usual OB/GYN providers. Because of her age, the option for aneuploidy screening was discussed with her by our REI docs even before she left their care and apparently again once she crossed the threshold of her private doctors’ office. Her response of “What would I do about it anyway?” is one that I have heard too many times before to mention, but it usually leads to an immediate cessation of information exchange between patient and busy provider. I am sorry to say, I have come to realize that this is more related to denial mechanisms on the part of both patient and provider rather than a true lack of desire for information. Regardless, as part of her scheduled visit with us, a pre-ultrasound genetic counseling session was offered and also declined.

During the course of her ultrasound, it became readily apparent we had problems that required discussion. The baby girl was perfectly normal in size for her well-documented gestational age and had absolutely no visible gross abnormalities or soft markers for a chromosomal abnormality. The little boy, on the other hand, was two weeks behind in size, symmetrically ‘growth-restricted’, had intracranial abnormalities, micrognathia (small and recessed chin), and a complex congenital heart defect. The babies’ abdomens, side-by-side, were so strikingly different in size that the patient herself immediately recognized the difference and sat bolt upright in the bed the minute the image was displayed on the overhead monitor. “What’s wrong with my babies,” she asked? “Is this the twin-to-twin transfusion syndrome I have been reading about on the internet?”

In my position, the ‘buck stops here’, so I am not much for mincing words. I explained to her that her baby girl was normally grown and appeared to have no visible abnormalities. There was no evidence of a twin-to-twin transfusion sequence and that would be extraordinarily uncommon in babies from separate eggs, different genders, and completely separate placentas. Then I detailed the findings of her little boy. Before I could tell her why I thought the baby had these abnormalities, she interrupted and asked, “Can they be fixed inside or do we have to wait until after delivery?” It was at this point that I told her that it was very unlikely they could be fixed because the baby probably had a severe chromosomal abnormality – trisomy 18 – and was at high risk of either not surviving the pregnancy or dying shortly after birth. “How can that be?” she asked, “No one in my family has that or has ever had a baby with that kind of problem?”

“I’m sorry,” I said, “But this is something that you had no control over. The same conditions that increase your risk with age for having a baby with Down syndrome (trisomy 21), a process called nondisjunction, also can result in babies with other chromosomal abnormalities.” It was at this point that I saw in the dimly lit room, her husband, who had been completely silent to that point, gently sobbing in his chair. I picked up the ever-present box of tissues, walked around the examination table to him, held his shoulder, and told both of them that “I have just given you an awful lot of information. I am going to leave you alone for a few minutes and then we can talk some more. I would like to see if our Genetic counselor can spend a few minutes with you too….”